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<FONT color="green">001</FONT>    // Copyright 2007 Regents of the University of California.  May be used<a name="line.1"></a>
<FONT color="green">002</FONT>    // under the terms of the revised BSD license.  See LICENSING for details.<a name="line.2"></a>
<FONT color="green">003</FONT>    /**<a name="line.3"></a>
<FONT color="green">004</FONT>     * @author Tyler Close<a name="line.4"></a>
<FONT color="green">005</FONT>     */<a name="line.5"></a>
<FONT color="green">006</FONT>    package org.joe_e;<a name="line.6"></a>
<FONT color="green">007</FONT>    <a name="line.7"></a>
<FONT color="green">008</FONT>    import java.lang.reflect.AccessibleObject;<a name="line.8"></a>
<FONT color="green">009</FONT>    import java.lang.reflect.Field;<a name="line.9"></a>
<FONT color="green">010</FONT>    import java.lang.reflect.Modifier;<a name="line.10"></a>
<FONT color="green">011</FONT>    import java.util.Arrays;<a name="line.11"></a>
<FONT color="green">012</FONT>    import java.util.Comparator;<a name="line.12"></a>
<FONT color="green">013</FONT>    <a name="line.13"></a>
<FONT color="green">014</FONT>    /**<a name="line.14"></a>
<FONT color="green">015</FONT>     * This abstract class contains implementations of the equals() and hashCode()<a name="line.15"></a>
<FONT color="green">016</FONT>     * methods that satisfy the Selfless interface.  The provided equals() method<a name="line.16"></a>
<FONT color="green">017</FONT>     * computes equality of all fields using reflection.<a name="line.17"></a>
<FONT color="green">018</FONT>     */<a name="line.18"></a>
<FONT color="green">019</FONT>    public abstract class Struct implements Selfless {<a name="line.19"></a>
<FONT color="green">020</FONT>    <a name="line.20"></a>
<FONT color="green">021</FONT>        protected Struct() {}<a name="line.21"></a>
<FONT color="green">022</FONT>        <a name="line.22"></a>
<FONT color="green">023</FONT>        /**<a name="line.23"></a>
<FONT color="green">024</FONT>         * Tests for equality with another object.  An obect is equal to this one<a name="line.24"></a>
<FONT color="green">025</FONT>         * if it is of identical type and each field is equal for the two objects.<a name="line.25"></a>
<FONT color="green">026</FONT>         * The objects' fields are equal if both are null, or if their values<a name="line.26"></a>
<FONT color="green">027</FONT>         * return true for &lt;code&gt;equals()&lt;/code&gt;.  This implementation uses<a name="line.27"></a>
<FONT color="green">028</FONT>         * reflection to work for any subclass of &lt;code&gt;Struct&lt;/code&gt;.<a name="line.28"></a>
<FONT color="green">029</FONT>         * @param other candidate object<a name="line.29"></a>
<FONT color="green">030</FONT>         * @return true if it is equal to this object<a name="line.30"></a>
<FONT color="green">031</FONT>         */<a name="line.31"></a>
<FONT color="green">032</FONT>        public final boolean equals(final Object other) {<a name="line.32"></a>
<FONT color="green">033</FONT>            if (other == null || getClass() != other.getClass()) {<a name="line.33"></a>
<FONT color="green">034</FONT>                return false;<a name="line.34"></a>
<FONT color="green">035</FONT>            }<a name="line.35"></a>
<FONT color="green">036</FONT>            <a name="line.36"></a>
<FONT color="green">037</FONT>            // traverse class hierarchy, finding declared fields.  This is<a name="line.37"></a>
<FONT color="green">038</FONT>            // necessary since getFields() only returns public fields.<a name="line.38"></a>
<FONT color="green">039</FONT>            for (Class&lt;?&gt; i = getClass(); i != Struct.class; i = i.getSuperclass()) {<a name="line.39"></a>
<FONT color="green">040</FONT>                final Field[] fields = i.getDeclaredFields();<a name="line.40"></a>
<FONT color="green">041</FONT>                AccessibleObject.setAccessible(fields, true);<a name="line.41"></a>
<FONT color="green">042</FONT>                Arrays.sort(fields, <a name="line.42"></a>
<FONT color="green">043</FONT>                    new Comparator&lt;Field&gt;() {<a name="line.43"></a>
<FONT color="green">044</FONT>                        public int compare(final Field a, final Field b) {<a name="line.44"></a>
<FONT color="green">045</FONT>                             return a.getName().compareTo(b.getName());<a name="line.45"></a>
<FONT color="green">046</FONT>                        }<a name="line.46"></a>
<FONT color="green">047</FONT>                    });<a name="line.47"></a>
<FONT color="green">048</FONT>                for (final Field f : fields) {<a name="line.48"></a>
<FONT color="green">049</FONT>                    if (!Modifier.isStatic(f.getModifiers())) {<a name="line.49"></a>
<FONT color="green">050</FONT>                        try {<a name="line.50"></a>
<FONT color="green">051</FONT>                            final Object a = f.get(this);<a name="line.51"></a>
<FONT color="green">052</FONT>                            final Object b = f.get(other);                          <a name="line.52"></a>
<FONT color="green">053</FONT>                            if (a == null ? b != null : !a.equals(b)) {<a name="line.53"></a>
<FONT color="green">054</FONT>                                return false;<a name="line.54"></a>
<FONT color="green">055</FONT>                            }<a name="line.55"></a>
<FONT color="green">056</FONT>                        } catch (final IllegalAccessException e) {<a name="line.56"></a>
<FONT color="green">057</FONT>                            // Should never happen.<a name="line.57"></a>
<FONT color="green">058</FONT>                            throw new IllegalAccessError();<a name="line.58"></a>
<FONT color="green">059</FONT>                        }<a name="line.59"></a>
<FONT color="green">060</FONT>                    }<a name="line.60"></a>
<FONT color="green">061</FONT>                }<a name="line.61"></a>
<FONT color="green">062</FONT>            }<a name="line.62"></a>
<FONT color="green">063</FONT>            <a name="line.63"></a>
<FONT color="green">064</FONT>            return true;<a name="line.64"></a>
<FONT color="green">065</FONT>        }<a name="line.65"></a>
<FONT color="green">066</FONT>        <a name="line.66"></a>
<FONT color="green">067</FONT>        /**<a name="line.67"></a>
<FONT color="green">068</FONT>         * Calculates the hash code.<a name="line.68"></a>
<FONT color="green">069</FONT>         * <a name="line.69"></a>
<FONT color="green">070</FONT>         * This method will satisfy the contract of the hashCode method for any<a name="line.70"></a>
<FONT color="green">071</FONT>         * subclass of &lt;code&gt;Struct&lt;/code&gt;.  (two structs that are <a name="line.71"></a>
<FONT color="green">072</FONT>         * &lt;code&gt;equal()&lt;/code&gt; structs will always have the same hashCode).  The <a name="line.72"></a>
<FONT color="green">073</FONT>         * precise return value of this method is unspecified, and may change in<a name="line.73"></a>
<FONT color="green">074</FONT>         * future releases.<a name="line.74"></a>
<FONT color="green">075</FONT>         * @return a hash value<a name="line.75"></a>
<FONT color="green">076</FONT>         */<a name="line.76"></a>
<FONT color="green">077</FONT>        public final int hashCode() { <a name="line.77"></a>
<FONT color="green">078</FONT>            return getClass().getName().hashCode();<a name="line.78"></a>
<FONT color="green">079</FONT>        }<a name="line.79"></a>
<FONT color="green">080</FONT>    }<a name="line.80"></a>




























































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